Small, portable wireless communications devices, such as cellular telephone, PDAs and the like, face increasing challenges associated with the design of effective wireless communications antennas. Internal antennas are able to be embedded in an appealing form factor and are often used in wireless communications devices. However, a fixed antenna, such as a Planar Inverted-F Antenna (PIFA), exhibits reduced performance when placed next to a users head, such as during a cellular phone call. This performance reduction is due, for example, to some blockage of the signal radiating to or from the antenna. This blockage and reduced performance can be a problem in areas where the wireless communications signal coverage is poor.
One way of overcoming this reduced performance problem is to add an extendable antenna part, such as a quarter-wave or half-wave whip, to enhance the RF performance of the portable handset. However, a half wave antenna in the 800–900 MHz band generally has a length that does not fit, when collapsed, into small portable handsets. Furthermore, quarter-wave whip antennas generally do not provide a significant performance improvement relative to a PIFA.
Therefore a need exists to overcome the problems with the prior art as discussed above.